Hi, as you are feedinga big number of stuff, i wont go with any defiency.....If your PH is correct, the plant is able to absorb all nutes very well. i chek again and write you something in the comments later.....normally purpeling can have a lot of reasons, the easiest one is a genetic relation . but it can have la lot of resons starting from beeing stressed, a salt builtup, so she cant aborb.... up to your mentioned phosphorous def.